Add and identify excluded instances in compute CDM

Change-Id: If03893c5e9b6a37e1126ad91e4f3bfafe0f101d9
Implements:blueprint compute-cdm-include-all-instances

watcher/decision_engine/model/element/instance.py

@@ -42,6 +42,9 @@ class InstanceState(enum.Enum):
 class Instance(compute_resource.ComputeResource):
 
     fields = {
+        # If the resource is excluded by the scope,
+        # 'watcher_exclude' property will be set True.
+        "watcher_exclude": wfields.BooleanField(default=False),
         "state": wfields.StringField(default=InstanceState.ACTIVE.value),
 
         "memory": wfields.NonNegativeIntegerField(),